1. Field of the Invention
The present invention relates to a supercharged engine wherein a coolant to be used to cool air supplied from a supercharger in an intercooler is delivered under pressure to the intercooler by an electrically operated coolant pump.
2. Description of Background Art
A supercharged engine is known wherein a supercharger is disposed between cylinder banks of a V-shaped engine with a drive pulley mounted on a crankshaft of the engine and a driven pulley coupled to the supercharger. A drive belt is trained around and extends between the drive pulley and the driven pulley. See, for example, U.S. Pat. No. 6,079,394.
If an intercooler for cooling air supplied from the supercharger of such a supercharged engine is supplied with cooling water by a mechanically driven water pump, since the rate of cooling water depends on only the rotational speed of the engine, the rate of the cooling water supplied by the water pump needs to be set to a required rate of cooling water no matter how the intercooler is operating. Consequently, the cooling water may occasionally be supplied at a rate in excess of the actually required rate.
In view of the above problems, there has been known an electrically operated water pump that is capable of supplying a required rate of cooling water depending on how the intercooler is cooling the supercharging air. See, for example, Japanese Patent Laid-Open No. 2011-47288.
However, inasmuch as the electrically operated water pump includes an electric motor, it occupies a large space and may not be installed in a compact layout on a supercharged engine.